Notice from Microsoft today –
“We have recently uncovered an issue with this Service Pack 1 package that may prevent customers who have Service Pack 1 from deploying future public or cumulative updates. As a precautionary measure, we have deactivated the download page until a new package is published.”
This was posted on the SP1 download page.
Unfortunately, I have no further details. To my knowledge, we have not experienced any issues with SP1 at Perficient. We can anticipate once a new download is release for SP1, there will also be a Hotfix released for customers who have already installed it. We will update you with any further information as it becomes available.